Circuit interrupter



CIRCUIT INTERRUPTER Original Filed Dec. 23, 1930 i INVENTORS CASSEDY,JR.

ERIC R. C. COE WILLIAM F Patented Aug. 22, 1933 UNITED STATES PATENTOFFICE CIRCUIT INTERRUPTER V Eric R. c. Coe, Summit, and William F.Cassedy, Jr., Milburn, N. J., assignors to International CommunicationsLaboratories, Inc., Newark, N. J., a Corporation of New York Originalapplication December 23, 1930, Serial No. 504,280. Divided and thisapplication October 31, 1931. Serial No. 572,340

3 Claims. (Cl. 20024) This invention relates to duplex telegraphsystems, and more particularly to a device for sending suitable signalsthereover for line balancing.

This application is a division of our application Serial No. 504,280filed December23, 1930.

As is well known in the art, these signals have heretofore been obtainedby operating a hand key to send impulses to the line toaid in obtaininga balance, said impulses being either alternately positive and negative,or else of one polarity followed by an interval of no current. A morerecent method is that of causing a transmitting relay, under the controlof a vibrating relay, to send the impulses to the line.

.It is well understood by those versed in the art, that for ease inobtaining a closer balance, the impulses sent to line should be equal induration, and further that the duration of asingle impulse should beequal to that of the shortest signal sent out under operatingconditions.

The methods mentioned above have been found unsatisfactory in view ofthe speed at which duplex systems are now operated, and due to thevarying length of the impulses sent out.

For the sake of brevity, and in conformity with current nomenclature inthe telegraph art, such impulses will be referred to hereinafter asalternating current or a. c., it being understood that when suchreference is made it may mean either alternate positive and negativeimpulses of equal duration, or impulses of one polarity alternating withno current intervals equal in duration to the current impulses.

The principal object of this invention therefore, is to provide a devicewhich may be attached to a sending mechanism such as a tape transmitter,a keyboard transmitter, or a printer embodying a transmitter, fortransmitting a. c. for balancing purposes.

A further object of this invention is to provide a mechanism which" willtransmit alternating current impulses of unvarying length for balancingpurposes.

A further-object is to provide a device which may be easily cut in andout of the circuit by some convenient means.

A further object is to provide a switch actively connected to thebrushes of the device which will connect the line or local circuitthrough the device when the latter is placed in operation and which willshort circuit the device when the latter is rendered inoperative.

A clearer conception of the operation, construction and further objectsof the invention may be had from the following specification taken inconjunction with the. accompanying drawing in which: I

Figure 1 discloses a front view of the device;

Figure 2 is an end View of Figure 1;

Figure 3 is a top view ofFigure 1; I

Figure 4 discloses, the device secured to a printer;

Figure 5 is a schematic view .of the device inuse in a duplex telegraphcircuit; I

Figure 6 is a schematic view of a modified device in use in a duplextelegraph circuit.

The device comprises a base 1 on which is rotatably mounted a commutatorcomprising an inner solid ring 2 and an outer ring consisting ofsegments 3 and 4 secured .to a bakelitedisc 10. Segments 3 of the outerring are strapped'to ring 2 by straps 9. l

The commutator is secured toaishaft 5 joure naled in two upright arms 6and 7 secured to the base. Oil'cups 8 are provided for lubricating'theshaft bearings. Arm 7 is providedwith a portion extending above arm 6 toprovide. a bearing for one end of a small shaft 11. The other end ofsaid shaft extends through an arm 12 formed as shown in Figures 1 and 4.Secured to shaft 11 by screws 14 is a brush carriage 15 carrying brushes16 and 17 which are secured to the carriage 15 by a block 18 and screw19. 85

Secured to the extreme end of shaft 11 is a holder for a mercury switch20 enclosed by a guard 21. The mercury switch is of any well-known typehaving two electrodes which are connected to the brushes 16 and 1'7 byconductors 22 and 23. The other end of shaft 11 is reduced as shown at24 in Figure 3 to accommodate an arm 25 which is held in adjustedrelation with the shaft by a thumb nut 26.

The arm 25 carries a spring 27 and a washer 28 which co-operate with abracket 29 to form a positioning device and stop for the shaft 11,brushes 16 andl'? and switch 20. Secured to the switch guard 21 as shownin Figures 3 and 4 is a rod 30 which is adapted to move the'brushes 16and 17 in and out of contact with the commutator and also tip themercury switch.

A gear 31 is secured to the end of shaft 5 by a set screw 32. This gearis adapted to mesh with a worm 33 secured to the drive shaft of theprinter. As long as the printer is in operation, the commutator isrotated, but a. c. is sent out on the line only when the brushes arebrought, into contact with the commutator through the movement of rod30.

The preferred form of the device as shown in Figure 4 is adapted to besecured to the base of the printer or tape transmitter, the existingbolts such as 36 being used for fastening. The gear 31 meshes with theworm 33 which is driven by the printer motor 34.-

Figure 5 is a schematic showing of the device as used in a duplextelegraph circuit in which designates the line and 41 is a polarizedrelay ing two windings, namely, an operating winding 42 and a biasingwinding 43. The square 44 designates the transmitting apparatus. Likenumerals have been used for like parts of the device, namely 3 and 4 forthe commutator segments, 16 and 17 for the brushes, and 20 for themercury switch.

When the operator desires to transmit a. c. to obtain a balance, the rod30 is manipulated, mov ing the brushes 16 and 1'7 into contact with thecommutator and, tipping the mercury switch 20 tjol he position in whichthe mercury is out of contact with the electrodes. Positive battery fromthe transmitter 44 passes through brush 17, solid ring 2,"segment'sfi'gbrush 16 to ground through the winding 42 of r'e1ay41,thereby mov ng the armature to the left and sending negative current outover line 40-. When the brush 16 reaches segment4 which is not strappedto solid ring, 3,

the circuit throughwinding 42 islopened and the biasing winding 43"moves the armature to' the right, thus connecting positive current tothe line. The armature of r'elay 41 therefore changes positi'ii'ri e'ahtime that brush 16 passes from a live segment 3 to a dead segment 4 orVice versa, thereby causing a'. c. to be transmitted to line at. a

frequency con't'rolledby the rate of rotation of the With the switch 20in the position of Figure 2,

.- the mercury 45 (Fig. 3) is lodgedin the left hand end of the tubeaway from the electrodes. HOW- ever,1when the brushes 16 and 17 aremoved out of contactwith the commutator, the switch is tippedin theopposite direction and the mercury moves to the right end of the tubeinto contact with the electrodes, thereby closing the signalling circuitfrom transmitter 44 to line relay 41 and short circuiting the brushes.

Itis apparentfrom the above that thisdevice provides an easily operatedand simple means for providing a. c. for balancing. It will, also be apparent that without in any way changing the intention or application ofthe device, it may be provided with a third brush as shown in Figure. 6,bearing on anadditional solid ring 51 which is connected to the segments4.

, By connecting line 40 to brush 16, positive battery to brush 1'7 andnegative battery to brush 50 thedevicemay be used to send a. 0. directto line without the interyention of the transmitting re'lay. In suchcase the mercury switch 20 would connect the line to transmitter 44 whenthe brushes were moved out of engagement with the commutator.

What is claimed is: Y

1; In a circuit interrupter, a continuously rotated commutator, aplurality of brushes adapted to be movedinto and out of contact withsaid commutator and a mercury switch adapted to automaticallyshort-circuit said brushes when moved out of contact with saidcommutator.

2. A circuit .int'errupter comprising a base, a commutator rotatablymounted on said base, a plurality of brushes associated with saidcommutator, said brushes being secured to a shaft,"a switch secured tosaid shaft and means for causing said shaft to oscillate.

3. A circuit interrupter comprising a rotatable commutator and a shafttherefor, a plurality of brushes associated with said commutator, aswitch secured to said shaft, and means controlled by said switch fordis-associating said brushes from said commutator and for shortcircuiting saidbrushes. A

WILLIAM F. CASVSEDY, JR. ERIC R. C. COE.

